Section 349-23 (PDF) of the Toronto Municipal Code declares that:
No person keeping pigeons shall permit the pigeons to stray, perch, roost or rest upon lands, premises or buildings of any person or upon any public place in the City, except on the property of the person keeping the pigeons.
So all we have to do is figure out who owns all the pigeons in the city and ask him to confine his birds to his own property? We should be rid of them any day now.